A friend bought a used Hungarian SA-85M. The gun is in original, as imported, excellent condition. He has fired 60rnds through it and he says it doubled quite often (unintentional, not bumping) and on three rounds he pulled the trigger and nothing (no bang, NO CLICK, nothing). Upon clearing the action he discovered a round in the chamber that ejected while cycling the action and he also discovered that the hammer was in the forward (uncocked) position. The ejected rounds had a small dimple normal to freefloating firing pin designs. The ammo was current production Silver Bear. All three ejected rounds fired when loaded again. What would cause the hammer to follow the bolt carrier into battery?

Probably a bad fire control group.  Should be easily replaced.

Throw in a G2 FCG and make sure the gas port is clear. Since it's used you never know what someone else has done to the rifle, sounds to me like it's short stroking from not enough gas pressure ...

I have noticed something interesting about these SA-85s. Take a look at the fire control group, esp. the disconnector/sear. If it is anything like mine, it has a tail like the FA variant does. The modified pieces is typically the selector, and a notch has been milled out to keep it from holding the disconnector from retaining the hammer if the selector is not quite in the semi position. If some one has at sometime swapped out the selector, it will not have this section milled out, and this can result in the hammer following the bolt home when the selector is close to the middle position. Just check out the FCG, that is where your problem lies.

Quoted: Upon clearing the action he discovered a round in the chamber that ejected while cycling the action and Do you mean a round in the receiver, ejected from the chamber but not thrown out of the gun?

sorry, to clarify, ...as he cleared the action the chambered round extracted and ejected from the gun as normal.

it could be a bad disconnector spring, or you may just need to dremel the "tail" off of the disconnector as previously mentioned

Thanks to all for the response!